In this first of two episodes on COVID-19 vaccines, we give you a quick explainer on what to expect from vaccine trials and how to interpret news around it. Concerns have risen around Bharat Biotech’s vaccine candidate after Haryana Health Minister Anil Vij, who participated as a volunteer in the phase 3 trials for Covaxin, tested positive for COVID-19 two weeks after receiving the shot. As more vaccine candidates emerge, we are likely to hear of more such incidents. But it is important to remember, as we learn in this episode, that infections arising among some participants is actually part of the clinical trial design for most vaccines. Guest: Jacob Koshy, Deputy Science Editor, The Hindu. Coronavirus | About 130 Covaxin trial volunteers may test positive, says Bharat Biotech Find the In Focus podcast on Spotify, Apple Podcasts and Stitcher. Search for ‘In Focus by The Hindu’. Write to us with comments and feedback at socmed4@thehindu.co.in.